The design of the basic integral power steering gear has been improved in several ways over the past few years. The original basic design dates back to the R. H. Sheppard U.S. Pat. No. 3,092,083 issued June 4, 1963. This steering gear represents the first successful incorporation of a spool-type valve in the piston with washer springs mounted at opposite ends of the valve to provide the centering action. The springs of the U.S. Pat. No. De 3,092,083 are adjusted to slightly preload the springs against the ends of the valve by adjusting nuts or rings. The adjusting nuts in the original design are then locked in position by the assembly person by drilling a hole through the piston and into the nut and inserting a pin that provides a positive lock against rotation of the nut.
Prior to the present invention, this method of locking the spring adjusting nuts in position has been universally used in the Sheppard integral power steering gear. The method has been successful, but certain aspects of the locking arrangement left something to be desired and actually led to the present invention.
The need that arose and led to the present invention is the need for greater efficiency of the manufacturing process, which includes the initial adjustment of the nuts and initially locking the nuts in position. As described above, in the Sheppard system, a hole is drilled through the piston and into each nut for a final lock after the two nuts are set by the manufacturing technician. This technique of the present invention of providing an initial lock assures that the nuts do not move off the adjusted position as the drilling operation is carefully carried out. Furthermore, it was found previously that while the locking pin locks the nut against rotation, it was still possible to get some radial movement of the nut, especially in the direction directly in line with the locking pin. Thus, a better way of locking the nut not only rotationally, but radially in all directions is identified.
Thus, it is one object of the present invention to provide a spring washer adjusting arrangement for an integral power steering gear wherein the assembly and adjustment of the valve is improved.
It is another and related object of the present invention to provide an initial locking means for the adjusting nuts for the washer springs that do not allow the nut to move during the additional manufacturing step of drilling through the piston into the locking nut and pinning for the final lock.
It is another object of the present invention to provide an arrangement for locking the adjusting nuts in an integral power steering gear wherein the nut is both rotationally, as well as radially locked against movement.